I work for Husqvarna (McCulloch), repairing these saws
Does the chainbrake just need refitting or was it disengaged on disassembly so was under tension and the spring popped out on disasesmbly?
The 738,740,742,838 and 842 all have the same inboard clutch and brake
if the chainbrake popped appart refit the pivot pin to the chain brake if its still in the saw body it goes through the part that looks like a treffoil
then turn the trefoil so the lever is at the top, then carefully using gloves safety glasses etc hold the break body and press the spring thats sticking out against something secure I use the top of the jaws of my bench visethen press down hard but slowly carefully compressing the spring then push it across back into its channel.
now the brake is ready to be refitted , the sprocket will need to have been removed but its not nessasary to remove the centrifugal clutch
feed the chainbrake in so the rear part first carefully lining it up so the pivot pin goes in to the hole in the handle push the brake handle FORWARD to line up the mechanism then screw the 4 t25 screws in and refit the cluch drum/sprocket/ bar chain and cluch cover
I had a look in the IPAs for this series of saws but theres no exploded diagram of the chainbrake mech as its only available as a complete assembly, but I could take pics of the process next time I have one on my bench
Husqvarna Rework, March 2010